New dimension in viral hepatitis research

Chronic hepatitis B is the leading cause of hepatocellular carcinoma and a significant global health issue, affecting over 296 million people worldwide, with 15 million people coinfected with hepatitis delta virus (HDV) suffering accelerated disease progression. Recent advances in single-cell sequencing and spatial transcriptomics offer promising insights to improve the understanding of the liver's immune responses and hepatitis B virus (HBV)-infected cell distribution, with the final goal being the achievement of an HBV 'functional cure'. In this issue of eGastroenterology, Cross et al used the GeoMx nanostring digital spatial profiling (DSP) technology to study gene expression in the liver tissues of three patients (one HBV-monoinfected, one HBV/HDV coinfected and one HBV/human immunodeficiency virus (HIV) coinfected). Unlike other spatial transcriptomics techniques, GeoMx DSP allows targeted selection of specific tissue regions (regions of interest) for analysis, enabling precise gene expression mapping. The study revealed spatially distinct transcriptomic signatures related to immune features and viral burden, identifying a component of underinvestigated immune cells. Despite the small sample size, this proof-of-concept study demonstrates the feasibility of spatial transcriptomics in analysing HBV infections. Future advances, such as integrating viral proteins and nucleic acids, will enhance the understanding of spatial viral replication. Challenges in tissue processing, data analysis and costs remain before spatial transcriptomics can be applied as a diagnostic tool, but ongoing multiomics approaches offer promise for improved diagnosis and therapy.